Earliest is silvered brass with adjustable bands with top showing Expo logo and text “1934/A Century Of Progress Chicago.” Very tiny bit of silver luster loss but still Exc. Next is gold luster adjustable band metal ring with top view in enamel showing the iconic Space Needle with text “Seattle World’s Fair.” Couple of faint hairlines in the blue enamel but hardly showing. VF. Next are a pair of silver plastic rings from the New York World’s Fair 1964-1965. One is a flicker alternating between the text and a color scene of the symbolic Unisphere. Second is clear plastic dome above image of Unisphere surrounded by appropriate text. Last is silver luster adjustable ring with enamel logo on top surrounded by text “Expo ’74 Spokane, USA.” Exc. to Mint.